7.7 jap brass

[Tjbrown1101]

Anyone know of anything that can be reformed to make 7.7 jap?

[MUSTANG]

1. 30-06 has been used for decades to fabricate 7.7 Japanese Brass. (7.7x58 Arisaka).

2. I did same and documented my efforts to make the 7.7 Arisaka Brass from 30-06 in this thread: https://castboolits.gunloads.com/sho...der&highlight=

3. I used a RCBS 200 Sil boolit gas checks and sized in .314 Lee Sizing die. Groups were much larger than same boolit used in my 30-40, 308, 30-06, and 300 WinMag rifles. I have an NOE molde; 314-203-SP, that I will cast some boolits in this fall; and reshoot the 7.7 Arisaka again and see if it will shrink those groups.

[725]

Same as MUSTANG. Very easy from .30-06.

[GONRA]

GONRA sez - just remember 7.7x58 mm Japanese head diameter
is a little larger than .30-06 head diameter.
>>> Use yer hed when reloading! !! <<<

[Harter66]

Mine may as well be 7.92×57J as it has a .317 groove . I had about 50 IMI 8×57 and as it turned out the Hornady 8×57 neck die was perfect delivering a .316 ID on the brass .

There is a little more taper and of course the smaller dia neck that will slightly "stretch" the ×57 case to the desired 58mm with no trim .

[BJung]

Military 30-06 so you won't accidentally chamber it in a 30-06 later

[Rapier]

For decades there as no ammo available for the type 99 Ari, so many smiths just ran an 06 reamer into the chamber and called it good. The first 99 I bought, for $5, was like this. Hunted with it for several years. Of course the brass was seriously modified upon firing. Not hard to figure out what was what, as fire formed brass no longer fit in an 06 rifle or in 06 dies, just fit that rifle. Fast forward, about a dozen 99s and I kept a full up original. Found that the RWS brass was very soft compared to military 06 brass. So just full length sized and trimmed 06 brass to make 7.7 brass, which fire forms correctly and works just fine in the 99.
The 99's major problem is the groove diameter varies greatly gun to gun, so is necessary to slug the barrel and match the cast bullets, sized and weight, to the rifling. I found that the 170-180 grain RN bullets do well, sized to the actual groove diameter. The RN makes for a shorter bullet by weight.

[Wayne Smith]

30-06 brass, with a piece of clear tape around the base and trimmed to length. The tape allows the case to sit central in the chamber, so when it expands it expands equally in diameter. Then take the tape off and neck size.

[Texas by God]

I had a bubba type 99 that had Remington 700 sights. It shot Remington CL 180 gr .310” RN bullets into 2” three shot groups @100yds.
I made the 7.7s from 8x57 brass with one pass through Lee 7.7x58 dies.
I didn’t load them as hot as Norma does…..


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[Tjbrown1101]

Okay thank you all. I will give it a try

[Larry Gibson]

30-06 brass, with a piece of clear tape around the base and trimmed to length. The tape allows the case to sit central in the chamber, so when it expands it expands equally in diameter. Then take the tape off and neck size.

Excellent method which I also use. Measured the head diameter of some Norma factory 7.7 jap cases; they were .470 just in front of the extractor groove and .473 on the rim. That's smaller by .003 at the case head than the LC '06 cases I've used.

[Larry Gibson]

30-06 brass, with a piece of clear tape around the base and trimmed to length. The tape allows the case to sit central in the chamber, so when it expands it expands equally in diameter. Then take the tape off and neck size.

Excellent method which I also use.

"GONRA sez - just remember 7.7x58 mm Japanese head diameter
is a little larger than .30-06 head diameter.
>>> Use yer hed when reloading! !! <<<"

Measured the head diameter of some Norma factory 7.7 jap cases; they were .470 just in front of the extractor groove and .473 on the rim. That's smaller by .003 at the case head than the LC '06 cases I've used. I don't have any Japanese milsurp to measure.

[Sig556r]

LC 30-06 works well for me for 7.7jap & 8mm.
Haven’t used clear tape for concentricity which makes sense but wouldn’t it melt in chamber heat?

[Wayne Smith]

You only use it for the first shot, and no, I've never seen it melt. I've always taken it off after that first fireforming.

[Rockindaddy]

Had a Jap 99LMG years ago with 30 round magazines. There was no 7.7 mm Jap ammo except for expensive Norma ammo. Lubed up once fired 30-06 commercial brass and run em in the RCBS sizer die. Trim them and load em up with British 303 or Argentine 7.65 pulled boolits out of dud cartridges. They would run like grass through a goose! Fun gun! Was a lot of loading!!

[gwpercle]

30-06 brass, with a piece of clear tape around the base and trimmed to length. The tape allows the case to sit central in the chamber, so when it expands it expands equally in diameter. Then take the tape off and neck size.

This is a good trick to get brass that is concentric and it will last longer !
Gary

[paul edward]

It is a good idea to use military surplus 30/06 brass. This can help avoid caliber confusion.

You can reform 30/06 cases in one pass. Be sure to anneal the cases before loading. Trimming to 2.28" can be a chore unless you have a power trimmer. I use a tubing cutter to shorten the reformed cases before final trim with an LE Wilson trimmer and 30/06 shell holder.

I did not get good accuracy with my .311 cast gas check bullets from an old 311299 mold (barrel groove diameter slugged at .313). Got good accuracy with 150 gr Hornady .312 jacketed bullets.

[HumptyDumpty]

8mm Mauser. The neck will be a little short, but it hasn't caused me a problem. I have gone as far as simply swapping the projectile on surplus ammo with some 150 grain .312 projectiles that I had lying around (after resizing the neck with a 32 S&W die). It shot fine, and now I have fire-formed brass.